Ore-roasting apparatus



March 20, 1928.

TO Fl/El. UNDER PRESSURE TO GUL P/k/R/C ACID PLANT D. W BOWERS GRE ROASTING APPARATUS Filed Aug. 6, 1927.

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1'0 one 'srmRA TOR I Patented Mar. 20, 1928.

UNITED STATES.

DANA W. BOWEBS, OI WILDERNESS, VIRGINIA.

OBE-ROASTING APPARATUS.

Application filed August 6, 1927. Serial No. 211,230.

This invention relates to ore roasting apparatus and more particularly to an ore roasting apparatus especially intended for use in roasting gold bearing sulphide ores.

An important object ofthe invention is acid plant for conversion into commercial.

sulphuric acid.

A still further object of the invent-ion 1s to rovide a device of this character which wil be extremely simple in its construction and operation, which will not be critical either as to temperature or to the s eed of passage of the ores therethrough an which will be durable and eflicient in service.

These and other objects I attain by the construction shown in the accompanying drawing, wherein for the purpose of illustration is shown a referred embodiment of my invention and w erein:

Figure 1 is a vertical sectional view through ore roasting apparatus constructed in accordance with my invention;

Figure 2 is a'section on the line 2-2 of Figure 1.

Referring now more particularl to the drawings, the numeral 10 general y designates a cylindrical retort wall of refractory materialand having its upper end closed, as at 11. The refractory wall is preferably enclosed by an outer metallic case 12 embodying at its lower end a flange 1-3, by means of which the refractory wall is supported. Surrounding the retort in slightly spaced relation to the metallic wall 12 thereof is a cylindrical condenser casing 14: having conical upper and lower ends 15 and 16, which communicate with an exhaust tube 17 and an outlet ipe 18. The exhaust pipe 17 preferably lea s directly to a commercial sulphuric'acld plant (not shown), while the outlet 18 preferably leads directly to an extraction plant. Both the condenser casing and retort are supported by upwardly converging braces 19 which, intermediate their ends, are secured to the lower conical extens1on of the condenser casing, as at 20 and at the1r upper ends are secured to the fiange 13 .A blower 21 has its exhaust pipe 22 extended through and sealed to the condenser wall and into the wall of the retort 10, so that incoming air enters the retort tangentially. A fuel feed pipe 23 is in communication with a source of fuel under pressure and with the interior of the retort at right angles to the path of incoming air enterln theretort from, the exhaust pipe 22. spark plug 24 or other suitable igniter is let through the walls of the condenser and retort. The blower 21 has its inlet in communication with a hopper 25 or other suitable source of finely divided ore which is to be treated. It will be obvious that ore drawn into the intake of the fan is passed through the exhaust pipe 22, entering the retort 10 tangentially, with the result that it has a whirling or rotating motion within the retort and expands centripetally. Incoming air and ore striking the incoming fuel which is admitted at right angles thereto ignited by the igniter 24 or after a predetermined operation, during which the interior of the retort becomes highly heated b spontaneous combustion, with the result t at the finely divided ore, intermingled with the whirling air, during its downward assage through; the retort; is very highly eated;

The temperature for the ores referred to is preferably about 1,000 0., or that temperature at which the base betals contained in the ores are oxidized.

Within the upper-conical extension 15 of the condenser is arranged a spray head 26 forming a spray which passes downwardly over the sides of the retort shell 12, cooling the same, and Washes gasespassing upwardfinely divides the same and this fuel is either a gases and ores, a portion of the water will be converted into steam and the gases will still retain a large proportion of their heat.

These heated gases, together with the contained steam, are led to a commercial sulphuric acid plant, thus eliminating the necessity for adding steam to the gases at the plant as a step in the production of the acid. In their passage, they preferably pass about the exhaust pipe 22 of the blower 21 which is of approximately one-half the diameter of the condenser outlet 17 and partially housed therein.

It is pointed out that by the use of finely divided ores, which should be of such size that they will pass through a one hundred rnesh screen, the roasting process is substantially instantaneous and is not dependent upon the length of time that the ores remain in the retort 10, with the result that the pressure or speed of the blower 21 is not critical. Furthermore, when these ores are introduced at a very high speed, with the result that they pass through the retort at a high speed, the blower action causes a finer division of the fuel and a hotter flame within the retort, so that the construction employed is substantially compensating and the temperature will vary with the speed of operation to insure proper roasting. It is pointed out that in the roasting of gold bearing sulphide ores, the contained sulphur provides fuel which, after the retort is heated to a predetermined extent, becomes active and enables a considerable reduction of the input of fuel to the retort. This is particularly true where the material is finely divided.

It has been found that by use of the method employed, stack gases are chemically free from gold, the heavier particles of which are precipitated when the gases make their abrupt change of direction in passing from the retort into the condenser space and the lighter particles of which are washed from the gases by the cooling liquid which. engages thereagainst at the time of their change of direction and for a considerable period thereafter. 1

Since the construction hereinbefore set forth is capable of a certain range of change and modification without materiall departmg from the spirit of the invention, I do not hmlt myself to such specific structure except as hereinafter claimed.

I claim 1. In apparatus for roasting ores and in combination, an open-bottomed vertically extending cylindrical retort, means for introduclng air under pressure with which the ore to be roasted is finely 'interminged to said retort at the upper end thereof and at 'such' an angle as to produce'rotation of the air andore means for introducing incomin fuel to t e retort in -the path of the incoming air and ore and means for washing gases passing from the lower end of the retort and for collecting ores removed by the washing process.

2. In apparatus for combination, an open-bottomed vertically extending cylindrical retort, means for introducing air under pressure with which the ore to be roasted is finely intermingled to said retort at the upper end thereof andat such an angle as to produce rotation of the incoming air and ore, means for intro-- ducing fuel to the retort in the path of the incoming air and ore, a casing surrounding the retort in spaced relation to the walls thereof and having at its upper end an outlet and at its; lower end an inlet, means at said upper end for. delivering a spray of cooling liquid and means at the lower end controllin the passage of liquid and ores from the lower end to maintain a predetermined liquid level therein.

3.In apparatus for roasting ores and in combination, an open-bottomed vertically extending cylindrical retort, means for in troducing air under pressure withwhich the ore to be roasted is finely intermingled to said retort at the upper end thereof and at such an angle as to produce rotation of the incoming air and ore, means for introducing fuel to the retort in the path of the incoming anand ore, a casing surrounding the' retort in spaced relation to the walls thereof and having at its upper end an outlet and at its lower end an inlet, means at said upper end for delivering a spray of cooling liquid, means at the lower end controlling the passage of liquid and ores from the lower end to maintain a predetermined liquid level therein and means for conducting exhaust gases passing from the upper end of the casing about the inlet for the retort to preheat the air and ore introducedthereto.

4. In apparatus for roasting ores and in combination, an open-bottomed vertically extending cylindrical retort, means for mtroducing air under pressure with which the ore to be roasted is finely intermingled to said retort at the upper end thereofand at such an angle as to produce rotation ofthe incoming air and ore,means for introducing fuel to the retort in the path of and at roasting ores and in right angles to the incoming air and ore.

and a washing condenser surrounding the retort and combiningtherewith to provide a conduit for gases passing from the lower 'end of the retort.

5. In apparatus for roasting ores and in combination, an open-bottomed vertically extending cylindrical, retort, means for mtroducingair under pressure with which the v ore to be roasted is finely intermingled to said retort at the upper end thereof and at such an angle as to produce rotation of the incoming air and ore, means for introducing fuel to the retort in the path of and at right angles to the incoming air and ore, a washing condenser surrounding the retort and combining therewith to provide a conduit for gases passing from the lower end of the retort, whereby the gases are caused to pass upwardly about the sides of the retort and means for washing the gases during their movement through the passage.

6. In apparatus forvroasting ores and in combination, an open-bottomed vertically extending cylindrical retort, means for introducing air under pressure with whichvthe ore to be roasted is finely intermingled to said retort at the upper end thereof and at such an angle as to produce rotation of the incoming .air and ore, means for introducing fuel to the retort in the path of and at right angles to the incoming air and ore, a washing condenser surrounding the retort' and combining therewith to provide a conduit for gases passin from the lower end of the ing fluid and ore from the last named means to thereby maintain the level of the washing fluid at a predetermined distance from the lower end ofthe retort.

In testimony whereof I hereunto afiix" my signature.

DANA W. BOWERS. 

